How Do I Know If it’s Safe to Exercise Outside?

When contemplating an outdoor workout, consider these factors:

1. Do you see smoke or haze? Can you smell smoke? These are strong indications to reschedule or relocate an intense workout, says Paul Kriegler, RD, CPT, director of nutrition product development at Life Time.
2. If you wear a fitness tracker that provides a performance indicator such as heart-rate variability (HRV), use that info to guide you during your workout. “Anytime I see a negative performance indication, such as lower-than-usual HRV, I pay extra close attention to how hard I push that day,” he notes.
3. Zero in on how you’re feeling. If you’re feeling sluggish, if you have a headache, or if you’re struggling more than usual, he advises, consider slowing your pace, reducing your intensity, or even stopping your workout. “The last thing you need to do is push yourself harder when the conditions are unfavorable.”
4. Look at the Air Quality Index (AQI) from AirNow.gov, which offers activity guidance based on ozone and particle pollution in your ZIP code. (Many weather apps also report the AQI.) When air quality is good, the AQI will be flagged as green — meaning it’s a great day to be active outside. Yellow indicates that sensitive groups, like those with asthma, should take precautions. Red and purple denote higher levels of ozone and particle pollution, suggesting that vulnerable individuals should reduce the duration or intensity of their workout — or skip it altogether.